Slide boards have been used as exercise devices by, for example, speed skaters or other athletes. Generally such slide boards include a slide surface with side bumpers. In use, the skater practices various foot strokes to increase strength and technique.
Olympic speed skaters, figure skaters, hockey players and skiers have demonstrated the efficacy of the slide board when training for the Olympics. Their device was simply a piece of plastic/formica countertop laminate with a piece of beveled two by four attached to each end. The purpose of the bevel was to reduce stress on the outside of the foot. Adjustment of the distance between the two by four end pieces was accomplished by drilling holes in the countertop and fitting one of the end pieces with pins which were inserted in the holes. The athletes wore terry cloth booties or heavy wool socks and pushed themselves from end to end closely approximating the movements utilized while training on an ice surface.
The significant shortcoming of this apparatus was the size and weight which made it awkward and dangerous to move. The base was particle board, a very dense material, with adhesive securing the formica gliding surface. Additionally, it was necessary to anchor the ends of the board to limit side to side movement with people, heavy weights, or a wooden frame.
Keppler, U.S. Pat. No. 4,779,862, discloses the entire countertop prototype which Olympians used with enhancements. Keppler's invention treats the base and gliding surface as separate elements, and thereby eliminates the adhesive which held the gliding surface to the base in the Olympians countertop prototype. The Keppler base is cut into sections and hinged while the plastic glide surface is rolled to improve movability. There is still significant weight for the total material package of the Keppler device as the only material eliminated was the glue while a much thicker, 0.375 inch gliding surface, replaced the thin formica used by the Olympians. Moreover, due to the flexible nature of the hinged base and its elevation, it is probably necessary to support the structure between the bumpers attached to each end and some type of anti-skid capability is apparently required to limit side to side travel of the apparatus. Thus, the devices used by the Olympians, and by Keppler have disadvantages with regard to set-up and transportation.
There are several devices on the market presently with constructions similar to Braathen, U.S. Pat. No. 5,133,700. Braathen refers to a gliding surface made of linoleum with a friction coating on the underside and start stop blocks attached to each end. Linoleum and the surfaces used in the similar constructions are typically at least 0.060 inches to 0.070 inches thick. These materials remain effectively rigid as the user slides across them. These materials are rigid enough to allow the device to be used on a surface such as padded carpet without buckling or wrinkling. With regard to flexibility, the only requirement is that the devices can be rolled up for storage.
Braathen and Carra, U.S. Pat. No. 4,940,226 incorporate adjustability into the end piece by squeezing the gliding surface between upper and lower members. Importantly, the members clamp the sliding surface when tightened by a vertically oriented releasable mechanism. Typically, the devices on the market using this design are ineffective. The end pieces move outwardly during use. This outward movement occurs when the lateral or horizontal forces generated by the exerciser are greater than the vertical forces applied by the releasable vertical connecting mechanisms as they clamp the upper and lower longitudinal members. It also appears that the concave-convex interlocking of the upper and lower members described by Braathen, column 2 line 12, would emboss the plastic sliding surface thereby leaving permanent distortion. Braathen's bottom support flange would also tend to move as there is no mention of any friction material to hold it in place.